This invention relates to a boat trailer having roller mounts that are adjustable when the boat support rollers are engaged by the hull of a boat being mounted on the trailer, to reposition the boat support rollers of the trailer so that they conform to the progressively changing shape of the boat hull as the boat is rolled onto the trailer.
Traditional boat trailers for transporting boats have roller assemblies mounted thereon for rolling boats onto and rolling the boats off of the trailer, and for firmly supporting a boat during transport while on the trailer. Almost all boat hulls have a compound curvature from stem to stem, so that the roller assemblies of most trailers are adaptable to the changing curvature of the boat as it is moved along the roller assemblies during loading and unloading of the boat with respect to the trailer.
Prior art roller mounts that support the rollers can include pairs of rollers on the ends of pivotal support beams, and the pivotal support beams usually are pivoted intermediate their ends about a centrally disposed axis. As a boat is loaded onto or unloaded from a trailer that uses conventional roller assemblies, the roller assemblies cross the strakes on the hull, and the compound curvature of the boat hull tends to urge some of the rollers to pivot out of contact with the hull. As a result, more of the weight of the boat is applied to the remaining rollers and the boat tends to assume a higher position on the trailer, thereby becoming more unwieldy and less stable.
A further problem caused by conventional roller mounts is that when the rollers cross the strakes on the boat hull, further instability and difficulty in loading or unloading the boat is created.
One method of dealing with these problems is to supply the trailer with a large number of rollers that are adjustable in their positions in response the changing shape of the hull of the boat as the boat is moved on or off the trailer. This increases the cost of the parts of the boat trailer and the assembly of the boat trailer, as well as increasing the cost of maintenance of the trailer. Also, this type of prior art roller support can be adequate for adjusting the heights of the rollers during the loading and unloading procedures, however, the angle of the hull of the boat also changes at the positions of the rollers and this is not accommodated by some prior art roller support designs.
A solution to some of the above noted problems is taught by my U.S. Pat. No. 5,316,329, which is incorporated herein by reference. The ""329 patent teaches pairs of rollers mounted on the ends of U-shaped pivotal roller mounting arms and the roller mounting arms are each tiltably supported intermediate their ends at the curve of the U-shape on saddles. When the shape of the boat hull changes at the positions of the pairs of rollers, the U-shaped roller mounting arms slide along their lengths in their saddles to adjust the relative height of the pairs of rollers. This maintains both rollers of each pair of rollers in constant load bearing contact with the changing shape of the boat hull at the position of the rollers. This construction has provided a means by which the rollers of the trailer can conform to the changing shape of the boat hull as it is drawn onto or rolled off of the trailer. However, the visual image of this structure is not particularly pleasing, the time for assembly of this structure is excessive and the assembly must be carefully accomplished in order for the structure to provide the desired alignment of the boat rollers with the boat hull and to avoid premature wear and damage of the parts. Also, it would be desirable to have a structure that is more stable and durable than the prior art. It is to these problems and desires that this invention is directed.
Briefly described, the present invention comprises a boat trailer having sliding boat trailer roller mounts for supporting the hulls of boats on the trailer that are adjustable to conform to the changing shape of the boat hull as the boat is rolled on or rolled off the boat trailer. Each sliding boat trailer roller mount includes a pivotal support beam that is supported intermediate its ends on the frame of the trailer so that it can tilt in response to the changing shape of the boat drawn onto the trailer. Notches are formed at the ends of the pivotal support beam for receiving the mounting blocks and the mounting blocks are mounted in the notches at the ends of the pivotal support beams. A roller mounting arm having at its opposite ends rollers rotatably mounted thereon is supported by each mounting block. The mounting block defines a shallow U-shaped channel and the intermediate portion of the roller mounting arm has a similar U-shaped configuration that is slidably mounted along its length in the U-shaped channel. This sliding relationship allows for the tilting of the roller mounting arm and its rollers so that when the shape of the boat hull drawn onto the trailer changes, requiring the rollers to change in relative elevation, the roller mounting arm slides longitudinally through the channel to accommodate this function.
The mounting block is formed in two identical segments that mate with each other to form the shallow U-shaped channel that supports the roller mounting arm. The notches of the pivotal support beam are sized so that the mounting block, assembled with its segments placed together about a pivotal support beam, slides into the notch. Once the mounting block is seated in a notch, it becomes perfectly aligned and firmly supported in its place, in full control of the pivotal support beam while allowing the relative sliding motion as described.
Thus, it is an object of this invention to provide an improved sliding boat trailer roller mount for supporting the hulls of boats on a trailer.
Another object of this invention is to provide the combination of a boat trailer with a sliding boat trailer roller mount for accommodating boats with hulls of various designs while providing adequate support for the boat hulls as the boats are drawn onto or discharged from a boat trailer.
Another object of this invention is to provide a durable, easily assembled, supportive, stable sliding boat trailer roller mount that adjusts to the changing shapes of boat hulls at the positions of the rollers as a boat is drawn onto or discharged from a boat trailer.